During lateral extrusion, pressure is applied to a work piece between two punches in such a way that some of the material flows—transversely to the press direction—into cavities formed by die halves.
A hydraulic closing device for lateral extrusion of work pieces is disclosed according to DE 199 22 659 A1, this closing device having two die halves which can be moved relative to one another and can be closed together and two punches which can be moved at the same speeds relative to the closed die halves, a first hydraulic piston, on which the first die half is arranged, being mounted in a displaceable manner in an axially movable first hydraulic cylinder, and a second hydraulic piston being mounted in a displaceable manner in a spatially fixed second hydraulic cylinder. The first punch is fastened via a punch carrier to a supporting plate which is connected to the ram. The second die half is arranged in a spatially fixed manner, and the second punch is fastened to the second hydraulic piston, which during the lateral extrusion can be acted upon by a pressure medium which can be displaced by the first hydraulic piston. Both hydraulic pistons have the same piston areas. The first hydraulic cylinder is arranged on a press ram; the second die is arranged on the second hydraulic cylinder. Both hydraulic cylinders are connected via an external pressure line to a pressure system which can be fed with pressure medium. A disadvantage in this case is the external high-pressure hose connection between the two hydraulic cylinders, since use of this moving high-pressure hose is currently only admissible for pressures up to 1000 bar.